Powerlimiter/Airrestrictor = realistic?

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MonGnoM

MonGnoM

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MonGnoM
So we have in GT6 a Powerlimiter. In the explanation it says that this limiter is an airrestrictor, which restricts the airflow going into the airintake and so reducing the power.

So real world race cars have the same system, but i wanted to ask, if the power/torque curve will look the same when they are restricted?
Because i´limiting the power kind of "cripples" the whole curve
 
This is a pretty interesting question. I know that back in the '80s, Formula One teams ran their cars at full power in qualifying, replaced the engine for the race, and then ran the engine at only a fraction of the power for the main event, otherwise the engine would explode after an hour. Even with the reduction in power for the race, these cars still had an insane amount of torque. I believe that the same applies in Formula One today. So I would assume that they have a similar torque curve, but perhaps somebody here is better qualified to answer this question than myself.
 
I can only imagine it was for the sake of making things easier on themselves. Just make it so the cars do not spin the tires as much on throttle application and top speed is lower and bam instant power reduction. I've often wondered if the power curve is really simulated anyway is there any proof it is?
 
CraigHyphenO
This is a pretty interesting question. I know that back in the '80s, Formula One teams ran their cars at full power in qualifying, replaced the engine for the race, and then ran the engine at only a fraction of the power for the main event, otherwise the engine would explode after an hour. Even with the reduction in power for the race, these cars still had an insane amount of torque. I believe that the same applies in Formula One today. So I would assume that they have a similar torque curve, but perhaps somebody here is better qualified to answer this question than myself.
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When they had qualifying engines they could run them with reduced cooling and increased boost, over 1,300hp in quali and down to about 1,000hp in the race. The quali engines and gearboxes only lasted a few laps.

In 2006 when they went from 3L V10s down to the 2.4L V8s Torro Rosso were allowed to use an air restricted (and rev limited) V10 and there were some teams making noises that they still had an advantage of 80-100 hp
 

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Johnnypenso
No, not even close. You don't restrict airflow and suddenly get a completely flat torque and power curve. Nowhere close to realistic.

Also this: https://www.gtplanet.net/forum/threads/unrealistic-powerbands-and-rpm.322171/
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You're right. Furthermore, I think the power-restricted cars have an advantage since they get to the max power and torque figures sooner in the RPM range and just stay there because of/thanks to the limiter.

This being said, I may have a plausible theory. I've not fiddled much with cars in real life, but I did with bikes. Now, there are two types of limiters on motorcycles: hardware and software, but their action is very similar. The hardware one is as simple as it gets: it's a piece of plastic that limits the travel of the throttle grip. This basically means it's limiting the revs to a certain amount. So if the max power or torque point is higher than (or just at) that point, their respective curves will theoretically reach a point where they will flatten and stay there - just as they do in the game. Of course, we don't see this in GT, as the revs keep reaching their normal upper limit. But the effect would be the same.
 
An engines output is a result of the amount of fuel and air that you can get into the combustion chamber, the more fuel and air you can fit in the bigger the resulting explosion will be and the more energy it will generate (there is also the mechanical efficiency aspect of engine design but we'll leave that out for the time being).

Restricting an engine in real life is done by simply restricting the amounts of air and fuel that can enter the combustion chamber, the less fuel and air you have the less power you get. This can be done by restricting fuel injector size, carburettor needles, fuel pump size/speed, air inlet/filter size restriction and turbo/supercharger volume limits. These effects can also be implemented by using the cars ECU to address the fuel/air balance and prevent the car from making maximum power.

A flat power curve like we see in GT6 when applying the limiter is not a realistic response but writing an algorithm that would apply a realistically adjusted power curve for over 1000 different cars using a variety of engine designs would be all but impossible. 👍
 
DolHaus
A flat power curve like we see in GT6 when applying the limiter is not a realistic response but writing an algorithm that would apply a realistically adjusted power curve for over 1000 different cars using a variety of engine designs would be all but impossible. 👍
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I don't think writing an algorithm to cover 1000 different cars is necessary, you need only write an algorithm to cover the various engine configurations and it doesn't need to match real life to the 5th decimal place either. Close enough would be good enough. Even if they took the existing curve and shrunk it, it would be better than what we have now.
 
Johnnypenso
I don't think writing an algorithm to cover 1000 different cars is necessary, you need only write an algorithm to cover the various engine configurations and it doesn't need to match real life to the 5th decimal place either. Close enough would be good enough. Even if they took the existing curve and shrunk it, it would be better than what we have now.
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No matter what they do someone will complain that they didn't do it right :lol:
 
I'd prefer the in-game power limiter to reduce power/ torque by the same percentage across the entire rev range.

power curve stays exactly the same, but simply less of it, everywhere
surely that's not hard to code..?
 
DolHaus
A flat power curve like we see in GT6 when applying the limiter is not a realistic response but writing an algorithm that would apply a realistically adjusted power curve for over 1000 different cars using a variety of engine designs would be all but impossible. 👍
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The power multiplier that the game engine probably still as a hidden part of the car specs would do a reasonable job of emulating it if they made it work like it did in GT3.
 
I look at it as if you are putting in a completely new lower powered engine, which is kind of realistic except for the flat power and torque. For example that's how to rationalize the 2J, by reducing 50% power to get to below 600pp you need to put in a smaller engine with less HP. This would be possible for a Track Day event.
 
Thing back to the original GT game, and you modded an R32 GTR to have 900HP?
It had nothing under 5000rpm and was even hard to launch without bogging down and having no boost.

Apply the GT6 Power limiter to that power curve, it would be totally undrivable with a power band of 500rpm
 
Tornado
The power multiplier that the game engine probably still as a hidden part of the car specs would do a reasonable job of emulating it
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This. Wouldn't a "more accurate" method of power limiting be really, really easy to do by just reversing the power multiplier like the one they use for the tuning parts, instead of just a capped achievable power number? That way the whole hp/torque curve will be lowered decrementally and retain it's character, instead of the peaks being sliced off and turned flat as a pancake.
 
I thought the GT power limiter worked by "restricting the fuel flow into the engine" which would create a flat power curve? I might be missing something but I believe that is the case, not necessarily "air restrictor"

Also, only the powerband is flat, but the torque curve IS NOT. Torque drops off MASSIVELY as soon as the power limiter kicks in, so everybody claiming that the game gives flat torque bands is incorrect.
 
To some degree ( small percentage ) of limiter in GT6 works quite okay, similar to ECU tuning to get better torque, sacrificing HP ( for example using timing retardation, leaner fuel mixture ) I saw some GT3 cars spec and most of them retains peak torque figure of original spec ( unrestricted ) even with BOP restriction ( often loses 30-50+HP ). BOP also usually mandate certain ECU map to keep teams gaining unfair power/torque curve, so that means they can alter what the curve look like after being restricted of air/intake.
 
DolHaus
A flat power curve like we see in GT6 when applying the limiter is not a realistic response but writing an algorithm that would apply a realistically adjusted power curve for over 1000 different cars using a variety of engine designs would be all but impossible. 👍
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There are several engine dyno simulations out there. It wouldn't be too complicated to add something like that into the GT series, choose your components, a one time calculation of tq and HP and go about your day. The intake restriction would have be the same as a rebuild/modification, just limit the CFM and go.

I'd rather they did that.
 
KinLM
I thought the GT power limiter worked by "restricting the fuel flow into the engine" which would create a flat power curve? I might be missing something but I believe that is the case, not necessarily "air restrictor"

Also, only the powerband is flat, but the torque curve IS NOT. Torque drops off MASSIVELY as soon as the power limiter kicks in, so everybody claiming that the game gives flat torque bands is incorrect.
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The torque curve also flattens out but in the middle of the rev range, not the peak where the power tends to flatten out. You can have torque peaks of several thousand rpm perfectly flat on some cars.
 
Johnnypenso
You can have torque peaks of several thousand rpm perfectly flat on some cars.
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A flat torque curve gives you a steadily increasing power curve.
If you have any examples of such torque curves that are the result of power limiter please share.
 
Vegard
A flat torque curve gives you a steadily increasing power curve.
If you have any examples of such torque curves that are the result of power limiter please share.
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Buy or get into the Zonda C12. Power limiter to 50%. Observe. Take any 4wd car with huge midrange torque and do the same, same result.
 
Johnnypenso
Looks like I was mistaken. My apologies.
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Not sure you were I think it may have changed at some point, I am sure you used to get a flat torque curve which is why restricted cars had such a huge acceleration advantage over a similar HP "base" setup.
That at least looks like it doesn't give such a huge advantage anymore.

A rough more realistic curve should be easy enough to do though, something simple like reducing power & torque across the range by the % on the slider. Modified slightly by the revs, lower revs lose slightly less than higher revs as its harder to produce power at high revs.
You would end up with a very similar curve to the original which is very marginally "fatter" at low rpm.

As a side note though why worry many people seem to run around with stage 3 weight reduction which is pure fantasy in most cases. Any car that sheds that much weight would be built from the ground up on a custom chassis so using the base car as the handling model is rubbish.
This power restriction method just adds to the fantasy, simple solution is don't put yourself in the situation where you need to use it by more than a couple of %.
 

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